Broadcast Reveiver作用

Broadcast Reveiver作用以及为何要引入（用来接收系统以及自定义消息的）

在系统内通知和判定执行状态

1，系统执行状态，开机了，TF卡插拔，准备关机，电量低了，

2，自定义执行状态，发消息提示更新界面

点击后会打log：顺序是testbroadcast2，testbroadcast

activity代码-----

package com.paoyx;

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

public class BroadcastActivity extends Activity {

    /** Called when the activity is first created. */

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        //设置按钮

        Button button = new Button(this);

        button.setText("send message");

        setContentView(button);

        button.setOnClickListener(new OnClickListener() {

			//按钮点击事件

			public void onClick(View v) {

				//设置intent传递数值

				Intent intent = new Intent();

				intent.setAction("com.paoyx.broadcast");

				sendBroadcast(intent);

			}

		});

    }

}

2个receiver代码---

package com.paoyx;

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.util.Log;

public class MyReceiver extends BroadcastReceiver {

	public void onReceive(Context context, Intent intent) {

		// TODO Auto-generated method stub

		if (intent.getAction().equals("com.paoyx.broadcast")) {

			Log.i("log","testbroadcast");

		}

	}

}

package com.paoyx;

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.util.Log;

public class MyReceiver2 extends BroadcastReceiver {

	@Override

	public void onReceive(Context context, Intent intent) {

		// TODO Auto-generated method stub

		if (intent.getAction().equals("com.paoyx.broadcast")) {

			Log.i("log","testbroadcast2");

		}

	}

}

menifest注册监听代码---

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.paoyx"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="8" />

    <application

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name" >

        <activity

            android:name=".BroadcastActivity"

            android:label="@string/app_name" >

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

        //注册receiver，并设置优先级别，数值大的优先，所以先启动MyReceiver2

        <receiver android:name=".MyReceiver">

            <intent-filter android:priority="1">

                <action android:name="com.paoyx.broadcast"/>

            </intent-filter>

        </receiver>

         <receiver android:name=".MyReceiver2">

            <intent-filter android:priority="2">

                <action android:name="com.paoyx.broadcast"/>

            </intent-filter>

        </receiver>

    </application>

</manifest>